I am doing you a disservice with the following recommendation.
However here it is.
Install a Channel Master CM4228HD antenna in the attic.
Aim the CM4228HD at about 326 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Run Separate coax from the CM4228HD to the Tv.
Do not use the jointenna.
The HD7015 and CM4228HD are 2 Separate antennas systems.
And are not connected together on to 1 coax.
Use Remote control A/B antenna switch at the Tv location to change from one antenna to the other antenna.
http://www.mcmelectronics.com , #32-4425.